Electric horn



Nov. 10, 1942. J, WHITE 2,301,487

ELECTRIC HORN Filed Feb. 28, 1940 k &5 i.

' M M ATTORNEY? Patented Nov. 10, 1942 2,301,487 ELECTRIC HORN JoeWhite, Anderson, I nd., assignor to General Motors Corporation, Detroit,Mich-., a corporation of Delaware Application February 28, 1940, SerialNo. 321,177

1 Claim.

This invention relates to horns operated by vibratory electric motorswhich comprise an electromagnet, a movable armature connected with thehorn diaphragm and a circuit breaker controlled by movements of thearmature for controlling the circuit of the electromagnet.

An object of the invention is to provide for the facile adjustment ofthe circuit breaker.

Another object of the invention is to provide for adjusting thefrequency of vibration of removable parts including the diaphragm anddiaphragm operating armature.

In carrying out these objects, I provide the circuit breaker with a leafspring member, the free end of which is located in the path of movementof the armature. I also provide the frequency adjuster with a similarleaf spring member located diametrically opposite to the leaf springmember which forms a part of the circuit breaker. The leaf spring memberof the frequency adjuster is likewise located in the path of movement ofthe armature. To a certain extent the pressure exerted upon the armatureby the leaf spring member of the circuit breaker tending to unbalancethe armature on one side is counteracted by a somewhat equal andopposite tendency to unbalance the armature on the other side due to itsengagement with the leaf spring member of the frequency adjuster.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawing wherein a preferred embodiment of the invention is clearlyshown.

In the drawing:

Fig. 1 is a side View partly in section of a horn embodying the presentinvention, said section being taken on the line of Fig. 2.

Fig. 2 is a bottom plan view of an assembly of Y a frame andelectromagnet structure shown in Fig, 1, together with a circuit breakerand an armature frequency adjuster.

Fig. 3 is a sectional View on the line 3-3 of Fig. 2.

Fig. 3a is a detail of structure on an enlarged scale.

Fig. 4 is a view of the circuit breaker disassembled from the frame ofthe horn motor, said view looking in the direction of arrow 4 of Fig. 3.

Fig. 5 is a view of the circuit breaker spring also looking in thedirection of arrow 4 of Fig. 3.

Fig. 6 is a sectional view on the line 66 of Fig. 2.

Referring to Fig. 1, the horn comprises castings and 2|, which togetherprovide a spiral 55 insulated contact 43.

passage 22 which starts from a throat 23 at the center of the horn andterminates in a bell-mouth at 24. The casting 20 cooperates with amovable steel diaphragm 25 to provide an air compression chamber 26.Diaphragm 25 supports an armature 3|! which, together with a. spacingwasher 3| and a clamping washer 32 are secured to the diaphragm and toeach other by a screw The armature 33 forms a part of thediaphragm-actuating vibratory motor which is housed by a stamped metalframe 34 which, together with the diaphragm 25 is secured to the base 20by screws 35 and nuts 36. Frame 34 supports a central magnetizable core31 and a magnetizable field member 38 which presents pole pieces 39 tothe armature 30. The core 31 is surrounded by magnet coil 40.

The armature 3U cooperates with a circuit breaker which includes a leafspring blade member 4| carrying a contact 42 normally engaging a contact43 carried by a bracket 44. Bracket 44 is located between insulatingplates 45 and 45. The parts 4|, 44, 45 and 46 are attached to ahinge-plate 41 by rivets 49 insulated from part 44 by bushing 49a. (Fig.6). The hinge-plate 47 is provided with a tapped hole 50 for receiving ascrew 5| having a tapered head 52 received by a similarly tapered recessprovided by a flange 53 struck inwardly from the frame 34. The flange 53is received by a round hole 54 in the leaf spring member 48. 'Thehinge-plate 41 provides an annular boss 41a surrounding the tapped hole50. The boss 41a is received by a hole 55 in the leaf spring member 48,thus providing for the proper location of the leaf spring 48 relative tothe hinge-plate 41. The contact bracket 44 is not in contact with thescrew 5| since the screw 5| clears the edges of the hole in bracket 44through which the screw passes.

The circuit of the horn is not illustrated, but it Will be understoodthat the horn carries an insulated terminal which is connected with theelectromagnet 40 which in turn is connected with the The circuit of thehorn is completed to ground through the non-insulated contact 42 havingmetallic electrical connection with the horn frame 34 which is grounded.

'I'he hinge-plate 41 is notched at 41b to provide separate feet 410which engage an inner surface of the frame 34. When the'screw 5| isscrewed into the tapped hole of the hinge-plate 41, the distance betweenthis plate and the frame 34 is decreased against the action of the leafspring 48. This causes the circuit breaker assembly to pivotcounter-clockwise at the places where thefeet 410 of plate 41 engage theframe 34. The screwing of the screw into the hinge plate 41 thereforecauses the blade 4| to move toward the armature 30. The unscrewing ofthe screw 5| will release the spring 48, thereby causing the blade 4| tomove toward the right and away from the armature 30. In this way theinstant of separation of the circuit breaker contacts 42 and 43 relativeto the armature 30 is adjusted.

The armature 3|) cooperates with a frequency adjuster formed'of severalof the same kind of parts which are used to form the circuit breaker.The frequency interrupter comprises a hingeplate 41, a U-shaped leafspring 48, a blade 4| and a plate 46 all riveted together by rivets 49.A screw 5| having a head 52 received by a recess provided by an annularflange 53 of the frame 34 cooperates with the hinge-plate 41, just as inthecase of thecircuit breaker, to adjust the free end of theleaf spring4| relative tothearmature 3!]. The frequency of vibration of thearmature 3D and of the diaphragm 25 depends upon the amount of pressureexerted by the blade 4| upon the armature. 3|! and this will depend uponthe duration of contact between the blade 4| and the armature 30 duringvibratory movement of the latter. Since the armature 30 is engaged bythe ends of similar leaf spring members 4| and 4| which contact with thearmature 3|! on diametrically opposite sides of the axis of core 31 andabout, the same distance from the core axis the forces exerted by thespring 4| upon the armature 33. will be somewhat counter-balanced by theforce, exerted by the spring 4|. There-. fore he Wfllb ubs ntial s mm ti al application of force to the armature and,

therefore, tendency to cook the diaphragm will be reduced.

The adjusting screws 5| are easily accessible since their heads arelocated on the outside of the frame 34 which provides an enclosure forthe horn motor.

While the embodiment of the present invention constitutes a preferredform, it is to be understood that other forms might be adopted, allcoming within the scope of the claim which follows.

What is claimed is as follows:

In a vibrator motor having a frame wall and an oscillatable assemblyspaced therefrom, an adjustable assembly adapted to be mounted on theframe wall and project into the path of movement of the oscillatableassembly, comprising in combination, a flat spring blade, an L- shapedhinge plate, a U-shaped leaf spring, and means securing them togethereach at one end and in stack assembly, and means for mounting the stackassembly on the frame wall, and for adjusting its relation to theoscillatable assembly comprising a single screw passing through theframe wall, the unsecured end of the leaf spring and threadedly engagingthe secured ends of the stack assembly, said hinge plate embracing theleaf spring and engaging the frame wall at a point intermediate themounting screw and the path of the oscillatable assembly to provide afulcrum about which the adjustable assembly may be moved throughactuation of the screw, said hinge plate acting as a thrust plateagainst which the spring blade tends to move whenit is engaged by theoscillatable assembly.

